1. Field of the Invention
The present invention relates to a plasma display device, and more particularly, to a plasma display device formed without an air gap in a connecting region of a tape carrier package (TCP) driver integrated circuit (IC). The present invention relates also to a method for manufacturing the TCP.
2. Discussion of the Background
Generally, a plasma display device displays images using plasma generated by a gas discharge. A flexible printed circuit (FPC) is typically used to couple display panel electrodes to a drive circuit. An IC may be formed on the FPC for selectively generating a wall voltage in pixels according to signals controlled in the drive circuit.
ICs formed on FPCs are widely used for applying voltages, and they may be formed on the FPC using a variety of known techniques, such as the chip on board (COB) and chip on film (COF) assembly methods. Tape carrier packages (TCPs) are becoming more popular because of the small sizes that may be achieved with them, as well as their low cost.
A TCP is a semiconductor chip packaging format utilizing tape automated bonding (TAB) tape. The TAB technology refers to the process of mounting and coupling a driver IC on the TAB tape's copper beam leads.
The TAB tape typically has circuit wiring patterned on a polyimide tape, and the beam leads are connected to the circuit wiring and exposed in a window region where the driver IC is positioned. A solder register layer protects the circuit wiring.
The TAB tape beam leads are coupled to a bump formed on a chip pad of the driver IC, thereby maintaining electrical and physical connections between the two. Further, an epoxy resin potting protects the driver IC from the external environment.
Thermal grease may be applied between the driver IC and a chassis base, or between the driver IC and a reinforcing member on the chassis base, so that heat may be quickly dissipated from the driver IC. A heat dissipating plate may also be mounted at an outer surface of the driver IC to emit heat to the outside.
However, the conventional TCP driver IC is not without problems. In particular, since an epoxy resin is deposited on a copper film of the FPC and a connecting section of the driver IC (i.e., a rear surface of the driver IC), once dried, a center area of the epoxy resin may have a depressed formation. This depressed formation may permit formation of a layer of air in the area when the depositing surface of the epoxy resin adheres to the chassis base or reinforcing member. This air gap reduces the driver IC's heat dissipating efficiency.
Furthermore, thermal grease is often applied to the deposition surface of the epoxy resin in order to reduce heat resistance caused by the air gap. In this case, the thermal grease may be forced outward from the epoxy resin when the driver IC is subsequently pressed onto the chassis base or reinforcing member. If the driver IC is removed and re-attached during assembly, the thermal grease may be depressed and therefore unable to fill the center area of the epoxy resin. Consequently, even when using the thermal grease, the epoxy resin's depressed formation and the layer of air may remain.
The air gap may permit excessive accumulation of heat generated by the TCP driver IC, thereby causing the TCP driver IC to breakdown and, in extreme cases, burst.